Two new species and a new genus of Cerambycidae are described from South America: Cotyclytus arriagadai sp. nov., from Bolivia; and Lembu dieguezi, gen. nov., sp. nov., from Paraguay. Orthomegas irroratus (Lameere, 1915) is redescribed, based on the second and third known specimens, and its distribution is expanded to include Ecuador. The male of Jamesia fuscofasciata Dillon and Dillon, 1952 is described and illustrated for the fi rst time, and the distribution of the species is expanded to Peru. Thirty-two new country records (twelve for Paraguay, fi fteen for Peru, two for Ecuador, three for Bolivia) and one new province record (Argentina) are presented.

The following four new species of Cerambycidae are described from Bolivia: Chrysoprasis imitatrix (Heteropsini); Carneades vigneaulti (Colobotheini); Colobothea larriveei (Colobotheini); Colobothea boliviana (Colobotheini). Esthlogena (Pseudotaxia) bella (Pteropliini) is described from Peru. A key to species of Carneades Bates, 1869 is provided. The other new species are included in previously published keys. Additionally, two new country records are reported for the fauna of Peru.

The following new species are described: Nyctonympha andersoni, sp. n., and N. howdenarum, sp. n., both from Colombia; N. genieri, sp. n., from Ecuador; N. taeniata, sp. n., from Trinidad; Falsamblesthis microps, sp. n., from Venezuela; Bactriola circundata, sp. n., from Brazil (Rio de Janeiro); B. maculata, sp. n., from Venezuela and Ecuador; and B. falsa, sp. n., from Brazil (Minas Gerais to Rio Grande do Sul). A redescription of Bactriola vittulata Bates, 1886, herein designated as the type species of the genus, is provided. Accurate data on the occurrence of Saepiseuthes chilensis Thomson, 1868, in Chile are given. Keys to the species of Bactriola Bates, 1886 and Nyctonympha Thomson, 1868 are added.